Python:将十六进制字符串转换为字节 [英] Python: Converting HEX string to bytes

问题描述

我正在尝试制作将通过UDP发送的字节帧.我有一个框架类，该类具有以下属性:同步， frameSize ，数据，校验和等我使用十六进制字符串表示值.像这样:

I'm trying to make byte frame which I will send via UDP. I have class Frame which has attributes sync, frameSize, data, checksum etc. I'm using hex strings for value representation. Like this:

testFrame = Frame("AA01","0034","44853600","D43F")

现在，我需要将这些十六进制值连接在一起，并像这样将它们转换为字节数组?！

Now, I need to concatenate this hex values together and convert them to byte array like this?!

def convertToBits(self):
    stringMessage = self.sync + self.frameSize + self.data + self.chk
    return b16decode(self.stringMessage)

但是当我打印转换后的值时，我没有得到相同的值，或者我不知道如何正确读取python表示法:

But when I print converted value I don't get the same values or I don't know to read python notation correctly:

This is sync: AA01
This is frame size: 0034
This is data:44853600
This is checksum: D43F

b'\xaa\x01\x004D\x856\x00\xd4?'

因此，第一个单词可以正确转换(AA01-> \ xaa \ x01)，但是(0034-> \ x004D)是不一样的.我尝试使用 bytearray.fromhex ，因为我可以在字节之间使用空格，但得到的结果相同.您能帮我通过UDP发送相同的十六进制单词吗?

So, first word is converted ok (AA01 -> \xaa\x01) but (0034 -> \x004D) it's not the same. I tried to use bytearray.fromhex because I can use spaces between bytes but I got same result. Can you help me to send same hex words via UDP?

推荐答案

Python显示可表示可打印ASCII字符的任何字节. 4 与 \ x34 相同，但是它选择在表示中打印ASCII字符.

Python displays any byte that can represent a printable ASCII character as that character. 4 is the same as \x34, but as it opted to print the ASCII character in the representation.

所以 \ x004 确实与 \ x00 \ x34 相同， D \ x856 \ x00 与 \x44 \ x85 \ x36 \ x00 和 \ xd4?与 \ xd4 \ x3f 相同，因为:

So \x004 is really the same as \x00\x34, D\x856\x00 is the same as \x44\x85\x36\x00, and \xd4? is the same as \xd4\x3f, because:

>>> b'\x34'
'4'
>>> b'\x44'
'D'
>>> b'\x36'
'6'
>>> b'\x3f'
'?'

这只是字节值的表示形式；该值是完全正确，您无需执行其他任何操作.

This is just the representation of the bytes value; the value is entirely correct and you don't need to do anything else.

如果有帮助，您可以使用

If it helps, you can visualise the bytes values as hex again using binascii.hexlify():

>>> import binascii
>>> binascii.hexlify(b'\xaa\x01\x004D\x856\x00\xd4?')
b'aa01003444853600d43f'

，您会看到 4 ， D ， 6 和?再次由正确的十六进制字符.

and you'll see that 4, D, 6 and ? are once again represented by the correct hexadecimal characters.

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